Medieval and renaissance glass technology in Valdelsa (Florence). Part 1: raw materials, sands and non-vitreous finds

A significant number of archaeological finds of the 13th–16th century from the Tuscan sites of Germagnana and Gambassi in Valdelsa—FI, was studied by different physico-chemical investigations (SEM–EDS, ICP, Mössbauer spectroscopy, XRD, XRF, TG-DTA) in order to contribute to clarify the production methodology and the pre-industrial glass manufacture technology. The studied samples are mainly non-vitreous finds as production waste, refractory materials, crucibles and raw materials; also vitreous finds as frits, skims, glasses (glass masses, glass working waste and finished products) have been taken into consideration. The obtained petrographic and physico-chemical data strongly suggest that both Gambassi and Germagnana glass manufactures were strictly connected with the sources of vitrifiable materials, situated in Tuscan sand quarries. In particular a comparison between sands from the neighbouring quarries and appropriate finds of the two archaeological sites evidences that the employed vitrifiable materials possibly belong to La Casina La Cava resort. The archaeological classification, based on macroscopic observation and stratigraphic position, was compared and verified with the scientific classification of the examined finds of Germagnana and Gambassi sites based on their composition, morphology and physico-chemical properties.     

A study of serum lipid profile part-1: Establishment of normal reference values of serum lipid levels in healthy vegetarian population of Gujarat

Fasting samples of 1329 apparently healthy vegetarian Gujarati population were tested for total cholesterol, triglycerides and three major fractions of lipoproteins, i.e. high density lipoproteins, low density lipoproteins and very low density lipoproteins. All the values showed marked increase with the age. Except for serum triglycerides, values differ in males and females in the age group of above 45 years. Compared to Northern Indian population low density lipoprotein and high density lipoprotein values were higher, but values of triglycerides and very low density lipoproteins were lower. There is no significant difference in total cholesterol values. Compared to Southern Indian population low density lipoprotein and very low density lipoprotein values were higher but values of triglycerides, total cholesterol and high density lipoprotein were lower. All serum lipid values were significantly lower than the Westem population. The range of values for both the sexes is presented for different age groups.     

Bond graphs for thermal energy transport and entropy flow

The transport of thermal energy in thermodynamics is described as the product of entropy flow and of the absolute temperature, in analogy to the volume flow and pressure in oil hydraulics and to electric charge flow (= current) and voltage in electronics. Bond graphs are shown to be especially suitable to describe the splitting of applied thermal energy into internal energy and external mechanical work. Transformers and the 0- and 1-junctions of Paynter can illustrate various entropy flow processes, including Carnot engines and heat exchangers. Entropy flow in heat conduction is distinguished from entropy convection, or transport by moving mass, where the entropy/temperature characteristic or equation of state is important. Irreversibilities are represented by impedance transformers reducing temperature and increasing entropy flow but conserving power.     

Feasibility of determination of fertile period in Indian women based on urinary hormone estimations

Baseline data available on the excretory profiles of estrone giucuronide (E₁G), pregnanediol glucuronide (PdG) and luteinising hormone (LH) on human menstrual cycles (n=104) was retrospectively analysed for identifying the limits of fertile period (FP) to be used as natural method of family planning. The limits of fertile period are suggested based on centile distribution of E₁G and PdG levels during defined phase of menstrual cycle. Two approaches, which do not involve any mathematical calculation are suggested. In approach A, fertile period is said to have started when E₁G value of 35 ng/ml is reached and is said to have ended when the PdG value of 2 μg/ml on two consecutive days is obtained. The criteria were applied to 30 test cycles in whom authentic fertile period was identified based on excretory profiles of E₁G, PdG and LH throughout the menstrual cycles. When approach A was followed the authentic fertile period was covered in 27 cycles giving an accuracy of 90% with a mean fertile period length of 9.11+1.9 days. In approach B, the cut off limit of E₁G value was increased to 55 ng/ml in order to reduce the days of abstinence. Though the length of the fertile period was reduced to 7.2+1.5 days the accuracy of the approach was 66.6%. Thus the approach A which has accuracy of 90% may appeal to determined couples who wish to practice family planning by periodic abstinence or restrict the use of barrier methods.     

Hopf bifurcation and synchronization of a five-dimensional self-exciting homopolar disc dynamo using a new fuzzy disturbance-observer-based terminal sliding mode control

Having found hidden hyperchaos in a 5D self-exciting homopolar disc dynamo, we study the existence of a Hopf bifurcation, which leads to unstable limit cycles bifurcating from a stable equilibrium. Hidden chaos with only stable equilibria can be observed from the Hopf bifurcation: a typical way to enable hidden attractors to be located. We then provide a new fuzzy controller, and a fast fuzzy disturbance observer, based on terminal sliding mode control for synchronization of the hyperchaotic system. Fuzzy inference is considered to weaken the chattering phenomena. Using Lyapunov stability theory, the stability of the closed-loop system is proved. Finally, simulations of synchronization are illustrated to show the efficient performance of the designed control method via external disturbances and dynamic uncertainties.     

The impact of education policy on economic development: Quantity,quality and earnings of labor

Education policy is viewed as affecting the content, and hence production functions, of different types of training and skill-formation. The relationship between skill type and level of education is considered. Optimal investment requires equating rates of return on the extensive and intensive margins, making endogenous the trade-offs between quantity and quality for each skill type. Selected education production functions are discussed with respect to implications for the distribution and levels of different skills and for skill-related earnings differentials. Equality of educational opportunity increases skill levels, upgrades the occupational structure and reduces relative earnings differentials.